Gene expression analysis of peripheral blood mononuclear cells prior to and following vaccination of human volunteers with the novel TB vaccine candidate MVA85A

Volunteers with a prior BCG vaccination were vaccinated with 1x10^8 pfu MVA85A either intradermally (id) or intramuscularly (im). Blood was taken immediately prior to vaccination (day 0) and 2 and 7 days post-vaccination. PBMCs were separated and frozen down. PBMCs were then thawed and RNA was extracted directly for microarray analysis. Some arrays contain control samples: from volunteers, incubated with either media alone or antigen 85, MVA85A or MVA wild type. These samples were used separately.

Data processing:The data were normalised using quantile normalisation with limma in R.

A greater understanding of the relationships between a vaccine, the immune response it induces, and protection from disease would greatly facilitate vaccine development. Modified Vaccinia virus Ankara expressing antigen 85A (MVA85A) is a novel tuberculosis (TB) vaccine designed to enhance responses induced by Bacille Calmette-Guerin (BCG). Antigen-specific interferon-? (IFN-?) production is greatly enhanced by MVA85A and peaks one week post-vaccination, however, the variability in response between healthy individuals is extensive. In this study we have sought to characterize the early changes in gene expression following vaccination with MVA85A and understand how these are related to long-term immunogenicity. 24 volunteers were vaccinated with 10^8 pfu MVA85A. 12 volunteers were vaccinated intramuscularly and 12 intradermally. Volunteers were healthy and did not have HIV, HCV, HBV or latent or active tuberculosis. Blood for this study was taken on the day of vaccination, immediately prior to the vaccine being given (day 0), and 2 and 7 days post-vaccination.